JP2019046890A - Adhesive transfer method for semiconductor device and transfer pin - Google Patents

Abstract

To solve such a problem that, when, during the assembly of a thin-sheet semiconductor chip for high frequency and high output applications, a conductive adhesive applied on a package is thick, the conductive adhesive rises up on the top surface of a semiconductor chip, so that even a conductive adhesive with high viscosity having high conductive performance and heat dissipation performance needs to be applied at a thickness thinner than that of a semiconductor chip.SOLUTION: A tip 3 of a metal pin 1 for applying a conductive adhesive 7 is subjected to fluorine-based resin coating 4 to provide a region of a metal exposed portion 5 where metal is partially exposed, so that an area to be applied with the conductive adhesive 7 and a height of the conductive adhesive can be adjusted.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adhesive transfer method for mounting a semiconductor device on a substrate by transfer of an adhesive, and a transfer pin thereof.

  A semiconductor chip constituting a semiconductor device is mounted on a substrate constituting a semiconductor package, and when the assembly is carried out, the semiconductor chip is die-bonded to the substrate. As one of the die bonding methods, there is one using transfer of an adhesive. In this case, the conductive adhesive in paste form is transferred and applied to the lower surface of the semiconductor chip, and the semiconductor chip is pressed against the substrate and adhered and fixed. The transfer of the adhesive and the mounting of the semiconductor chip are performed by an automatic device using a die bonder. Transfer of the conductive adhesive generally comprises the following steps.

1) Immerse the tip of a metal transfer pin (hereinafter, metal pin) in a conductive adhesive filled in a dish.
2) After step 1), a metal pin is pressed against the mounting surface of the substrate to apply a conductive adhesive.
3) After the step 2), the semiconductor chip is placed on the conductive adhesive applied on the substrate and pressed to fix the semiconductor chip.

  Here, when the semiconductor chip is fixed, the conductive adhesive overflows from the lower surface of the semiconductor chip. For this reason, it is necessary to prevent the conductive adhesive from adhering to the wire bonding pad or the electric circuit formed on the upper surface of the semiconductor chip. In order to avoid the adhesion of the conductive adhesive on the upper surface of the semiconductor chip, for example, a solution method as in Patent Document 1 has been proposed.

JP, 2014-207256, A

  In recent years, as semiconductor chips used for semiconductor devices for high frequency applications and high output applications, semiconductor chips having a thin chip thickness are used in order to secure frequency characteristics and heat dissipation. For example, the chip thickness of the high frequency and high power semiconductor chips is as thin as 80 μm to 150 μm. As described above, when the thickness of the semiconductor chip is reduced, it is necessary to suppress the thickness of the conductive adhesive to be applied sufficiently thin even in the semiconductor device as shown in the above-mentioned Patent Document 1. However, since the application of the conductive adhesive is performed using a metal pin as described above, when the viscosity of the conductive adhesive is high, the amount of adhesion to the tip of the metal pin is increased. When the conductive adhesive applied to the semiconductor package is thick, it climbs up on the top surface of the semiconductor chip and adheres to the wire bonding pad and the electric circuit on the top surface. Therefore, in order to apply the conductive adhesive in a thin and minute amount, it is desirable that the viscosity of the conductive adhesive be low.

  On the other hand, conductive adhesives generally improve conductivity and heat radiation performance by mixing silver filler into the adhesive, especially low resistance, high heat radiation type adhesive has high density of silver filler and viscosity of the adhesive Since it has a relatively high viscosity, it is difficult to apply a small amount of stable adhesive. In addition, since the high conductive performance and heat dissipation performance of the conductive adhesive are required along with the performance improvement of the semiconductor chip for high frequency applications and high power applications, the application of the minute amount of the above-mentioned adhesive is made more difficult. For this reason, the conductive adhesives that can be used are limited, which is a factor that makes it difficult to develop a semiconductor chip capable of high-performance and capable of automatic assembly of die bonding.

  The present invention has been made to solve the above-mentioned problems, and is characterized by obtaining an adhesive transfer method which enables stable and easy application of a minute amount of adhesive for semiconductor devices. I assume.

  The adhesive transfer method for a semiconductor device according to the present invention is a transfer pin consisting of a metal pin used for applying a conductive adhesive for bonding a semiconductor device to a mounting surface, and the metal pin is plural at its tip. And the fluorocarbon resin coating is attached to the side surface of the tip portion, and the tip surface of the protrusion portion is formed with a metal exposed portion for applying a conductive adhesive at the time of transfer. A part of the side surface around the tip surface is characterized by having a region of a predetermined height from which the fluorine-based resin coating is removed.

  In addition, a plurality of protrusions are formed at the tip, and a fluorine resin coating is attached to the side surface of the tip and a metal exposed portion is formed, and fluorine is provided at a predetermined height around a side surface of the tip surface of the protrusion What is claimed is: 1. A method for transferring an adhesive of a semiconductor device, comprising applying a conductive adhesive to a semiconductor device using a metal pin having a region from which a resin-based resin coating is removed, the tip of the metal pin being a conductive adhesive. A first step of immersing in the filled supply tray, a second step of moving the tip of the metal pin upward, and pressing the tip of the metal pin against the adhesive coated surface of the semiconductor device, A third step of applying a conductive adhesive and a fourth step of retracting the tip of the metal pin from the adhesive application surface of the semiconductor device are provided.

  According to the present invention, in the transfer of the adhesive to the semiconductor device, it is possible to apply the minute amount of the adhesive more stably and easily.

It is (a) top view, (b) side view, (c) side surface enlarged view, (d) bottom view for illustrating the composition of the transfer pin for adhesives transfer of the semiconductor device by Embodiment 1 of the present invention. FIG. 6 is a diagram showing a method of transferring the conductive adhesive of the semiconductor package according to the first embodiment. FIG. 7 is a view exemplifying a state in which the semiconductor chip is mounted on the semiconductor package by the transfer of the adhesive according to the first embodiment. (A) top view, (b) side view, (c) side surface enlarged view, (d) bottom view, to illustrate another configuration of the adhesive transfer metal pin of the semiconductor device according to the second embodiment. (E) It is sectional drawing.

Embodiment 1
An adhesive transfer method for a semiconductor device according to a first embodiment of the present invention and a transfer pin will be described below with reference to the drawings. FIG. 1 is a view illustrating the configuration of a transfer pin for adhesive transfer of a semiconductor device according to the first embodiment, wherein (a) is a top view, (b) is a side view, (c) is (b) FIG. 7D is an enlarged view of a part of the side surface of FIG. FIG. 2 is a view showing a method of transferring the conductive adhesive to the semiconductor package according to the first embodiment. FIG. 3 is a view exemplifying a state in which the semiconductor chip is mounted on the semiconductor package by the transfer of the adhesive according to the first embodiment. The transfer pin for adhesive transfer according to the first embodiment is a tool for applying a conductive adhesive, and is composed of a metal pin 1. The semiconductor chip 10 is mounted on a package mounting surface 9 of a substrate constituting a semiconductor package (not shown) by die bonding using an automatic assembling apparatus. The automatic assembling apparatus comprises a mounting portion 6, a 3-axis movable robot arm (not shown), a controller (not shown), a pedestal (not shown), a supply tray 70, and a mounting nozzle 11. Be done.

  As shown in FIGS. 1 and 2, the metal pin 1 is fixed to the mounting portion 2 and used. The mounting portion 2 is formed with a key seat, and is gripped by the grip portion of the mounting portion 6 provided on the automatic assembling apparatus (not shown) and mounted on the mounting portion 6. The mounting portion 6 is provided to a three-axis movable robot arm provided in the above-described automatic assembling apparatus. The above-mentioned automatic assembly apparatus drives an actuator of a 3-axis movable robot arm under control of a controller to move the mounting portion 6 three-dimensionally in the horizontal direction and the vertical direction and hold the metal pin 1 at the tip of the mounting portion 2 Position control is performed so as to move to the predetermined position. The metal pin 1 moves to a predetermined mounting surface on one or more semiconductor packages as the mounting portion 6 and the mounting portion 2 of the automatic assembling apparatus move in the horizontal and vertical directions, and transfers the adhesive. Further, the plurality of semiconductor chips 10 are respectively held by the semiconductor holding portions provided in the above-described automatic assembly apparatus, and move to the plurality of mounting surfaces to which the adhesive is transferred. Each semiconductor chip 10 is pressed against the transferred mounting surface of the adhesive and is die-bonded.

  Here, the metal pin 1 according to the first embodiment is formed by cutting, casting, forging or the like from a base material made of stainless steel. In the example of FIG. 1, the metal pin 1 is formed of a cylindrical base portion 30 and a tip portion 3 provided on the lower surface of the base portion 30.

  As shown in FIGS. 1 (b) and 1 (c), the distal end portion 3 is formed by projecting a projecting portion 50 from each of four corner portions at four corners on the bottom surface of the rectangular parallelepiped base column 40. The protrusion 50 has a rectangular parallelepiped shape whose side length is smaller than half of the side length of the base pillar 40. As a result, an air gap is formed between the adjacent protrusions 50, and as shown in FIG. 1D, a cross-shaped groove surrounded by the four protrusions 50 is formed. In addition, the four sides of the base column 40 are shorter than the diameter of the base portion 30, and as shown in FIGS. 1 (a) and 1 (b), the connecting surface between the base portion 30 and the tip 3 has a stepped shape. There is no. Further, in accordance with the area of the bottom bonding surface of the semiconductor chip 10, the dimension and shape of the bottom of the protrusion 50 of the tip 3 are determined.

  The tip 3 of the metal pin 1 is coated with a fluorine-based resin coating 4. The fluorine-based resin coating 4 adheres to the side surface and the bottom surface of the base pillar 40 of the tip 3 and covers the surface. Further, the fluorine-based resin coating 4 adheres to the side surface of the protruding portion 50 of the tip portion 3 and covers the surface. The bottom surface of the projecting portion 50 of the tip portion 3 and a part of the side surface of the bottom side peripheral edge form a metal exposed portion 5 in which the metal surface is exposed without the fluorine resin coating 4 adhering. The thickness of the fluorine-based resin coating 4 is about 30 to 100 μm.

  The exposed metal portion 5 has adhesion to the adhesive, and adheres the conductive adhesive 8 to the tip 3 of the metal pin 1. The fluorine-based resin coating 4 is non-adhesive to the adhesive, and the conductive adhesive 8 does not adhere. The fluorine-based resin coating 4 is not attached to the region of length (height) L from the bottom of the tip 3 shown in FIG. As a result, the adhesive is attached to each of the plurality of exposed metal portions 5 of the tip 3 of the metal pin 1, and the height of the attached adhesive becomes L.

  FIG. 2 shows a method of transferring the conductive adhesive of the semiconductor package using the metal pin 1 of FIG. 1, which follows the time course of the transfer process for applying the conductive adhesive 8 The process sequence of a)-(d) is shown. In the automatic assembling apparatus, the supply tray 70 is placed on a pedestal within the movable range of the metal pin 1, and the inner container of the supply tray 70 is filled with the conductive adhesive 7 before entering the transfer process. There is. In addition, the semiconductor package is placed in an area different from the installation area of the supply tray 70 on the pedestal.

First, the metal pin 1 is attached to the attachment portion 6 of the automatic assembling apparatus.
Next, in the first step (a) shown in FIG. 2 (a), the mounting portion 6 of the automatic assembling apparatus is moved upward, and the tip 3 of the metal pin 1 is lowered toward the supply tray 70 to supply The tip 3 of the metal pin 1 is dipped in the conductive adhesive 7 in the plate 70. At this time, the upper and lower positions of the mounting portion 6 are adjusted so that the fluorine-based resin coating film 4 of the tip 3 is dipped in the conductive adhesive 7 and the base 30 is not dipped in the conductive adhesive 7.

  In the next second step (b), under the control of the controller of the automatic assembling apparatus, the mounting portion 6 is moved upward, the metal pin 1 is lifted, and the state shown in FIG. 2 (b) is obtained. In this state, the surface tension of the fluorine-based resin coating film 4 is low and there is a water repellent effect. Therefore, the conductive adhesive 8 adheres only to the metal exposed portion 5 without adhering the conductive adhesive 8.

  In the next third step (c), the mounting portion 6 is moved in the horizontal plane by the control of the controller of the automatic assembling apparatus, and package mounting in the semiconductor package to which the conductive adhesive 8 is applied from the state of FIG. The metal pin 1 is translated to a position just above the surface 9. By lowering the metal pin 1 from the position, as shown in FIG. 2C, the exposed metal portion 5 to which the conductive adhesive 8 is attached contacts the package mounting surface 9, and the conductive adhesive 8 is mounted on the package Adhere to face 9 When using the metal exposure part 5 of FIG.1 (d), the conductive adhesive 8 adheres to four places.

  In the next fourth step (d), the mounting portion 6 is vertically moved by control of the controller of the automatic assembling apparatus, and when the metal pin 1 is lifted from the state of FIG. The adhesive 8 remains, the application of the conductive adhesive 8 is completed, and the transfer of the conductive adhesive 8 to the semiconductor package is completed. In the example of FIG. 2 (d), conductive adhesion transferred to a plurality of locations (four locations when using the metal exposures 5 of FIG. 1 (d)) corresponding to the metal exposures 5 on the package mounting surface 9 The agent 8 remains.

FIG. 3 illustrates a state in which the semiconductor chip 10 is mounted on the package mounting surface 9 after the conductive adhesive 8 of FIG. 2 is applied to the package mounting surface 9.
The semiconductor chip 10 is vacuum-adsorbed by the mounting nozzle 11 of the automatic assembling apparatus, and is conveyed above the transfer site of the conductive adhesive 8 on the package mounting surface 9 by the moving mechanism of the automatic assembling apparatus. Thereafter, the semiconductor chip 10 is mounted on the package mounting surface 9 with the bottom surface in contact with the conductive adhesive 8 on the package mounting surface 9. Further, by applying a load to the mounting nozzle 11 so that the semiconductor chip 10 presses the package mounting surface 9, pressure is applied to the conductive adhesive 8, and the conductive adhesive 8 wets and spreads on the lower surface of the semiconductor chip 10. At this time, in order to avoid adhesion of the conductive adhesive 8 to the upper surface of the semiconductor chip 10, the height H after completion of the application of the conductive adhesive 8 of FIG. 2D is made thinner than the thickness of the semiconductor chip 10. ing.

  Here, the height H and the area S of the conductive adhesive 8 applied to the package mounting surface 9 are the same as those of the conductive adhesive 8 attached to the metal exposed portion 5 of the metal pin 1 of FIG. It depends on the amount. The height of the conductive adhesive 8 applied to the package mounting surface 9 can be adjusted by adjusting the height L of the exposed metal portion 5 shown in FIG. 1C in advance. Thus, the adhesion of the conductive adhesive 8 to the upper surface of the semiconductor chip 10 when the semiconductor chip 10 of FIG. 3 is mounted can be suppressed.

  Furthermore, when the conductive adhesive 8 is applied, the exposed metal portion 5 at the tip 3 of the metal pin 9 comes in contact with the package mounting surface 9, but the contact at the tip 3 is covered with the fluorine resin coating 4. The structure is such that the metal portion is exposed at the metal exposed portion 5 instead of the structure shown in FIG. For this reason, the fluorine-based resin coating 4 does not wear and is excellent in durability.

  When the viscosity of the conductive adhesive 8 becomes high, the amount of the conductive adhesive 8 adhering to the exposed metal portion 5 at the tip 3 of the metal pin 9 increases. However, the adhesion amount of the conductive adhesive 8 can be suppressed by interposing the fluorine-based resin coating 4. As a result, since a low resistance and high heat radiation adhesive can be used as the conductive adhesive 8 and the semiconductor chip can be assembled automatically, it is excellent in high performance (low resistance, high heat radiation) and price reduction. Enables the provision of high frequency and high power devices.

  In the adhesive transfer method according to the first embodiment, a plurality of projecting portions 50 are formed on the tip end portion 3, the fluorocarbon resin coating 4 is attached to the side surface of the tip end portion 3, and the metal exposed portion 5 is formed. The conductive adhesive 7 is applied to the semiconductor device by using the metal pin 1 as a transfer pin having a region with a predetermined height L and the fluorine resin coating 4 removed on a part of the side surface around the tip surface of 50 A method for transferring an adhesive of a semiconductor device, comprising: a first step of immersing a tip portion 3 of the metal pin 1 in a supply plate 70 filled with a conductive adhesive 7; and an upper portion of the tip portion 3 of the metal pin 1 A second step of moving to the second step, a third step of pressing the tip portion 3 of the metal pin 1 against the adhesive coated surface of the semiconductor device, and applying the conductive adhesive 7, and a tip of the metal pin 1 Section 3 is connected to the above semiconductor device Characterized by comprising a fourth step of retracting from the agent-coated surface.

  The transfer pin is formed of a metal pin 1 used for applying a conductive adhesive 7 for bonding the semiconductor device to the mounting surface, and the metal pin 1 has a plurality of projecting portions 50 formed on the tip 3 thereof. The fluorocarbon resin coating 4 is attached to the side surface of the tip portion 3 and the tip surface of the protrusion 50 is formed with the metal exposed portion 5 for applying the conductive adhesive 7 at the time of transfer, A partial side surface around the surface is characterized by having an area of a predetermined height from which the fluorine-based resin coating 4 is removed.

  As a result, in the transfer of the adhesive to the semiconductor device, it is possible to apply the minute amount of the adhesive more stably and easily.

Second Embodiment
Although Embodiment 1 used the transfer pin which gave fluororesin coating 4 to the front-end | tip part 3 of the processed metal pin 9, it is not restricted to this shape.

  FIG. 4 is a view illustrating the configuration of a transfer pin according to the second embodiment, wherein (a) is a top view, (b) is a side view, and (c) is an enlarged view of a part of the side surface of (b) (D) is a bottom view, (e) is a cross-sectional view of (c). The metal pin 9 constituting the transfer pin according to the second embodiment has a structure in which the side surface and the end surface of the end portion 3 are covered with the fluorine resin coating 4. However, the front end portion 3 of the metal pin 9 is not covered with the fluorine resin coating 4 on the entire surface, and a part of the front end portion 3 does not have the fluorine resin coating 4. In the example shown in FIGS. 4 (d) and 4 (e), the fluorine resin coating 4 is not attached to the central portion of the tip surface of the tip portion 3, the metal surface is exposed, and the exposed metal portion is rectangular. It is formed. The exposed metal portion 5 functions as an adhesion area of the conductive adhesive 8 when the conductive adhesive 8 is applied.

  The configuration other than the above and the transfer step for applying conductive adhesive 8 using metal pin 9 shown in FIG. 4 are substantially the same as in the first embodiment, and therefore the description thereof will not be repeated.

  The transfer pin according to the second embodiment comprises a metal pin 1 used for applying a conductive adhesive 7 for bonding a semiconductor device to a mounting surface, and the metal pin 1 is made of fluorine resin on the side surface of the tip 3. The coating 4 is attached, and the central portion of the tip surface of the tip portion 3 is characterized by having a metal exposed portion 5 from which a fluorine-based resin coating is removed for applying a conductive adhesive at the time of transfer.

  As described above, by providing the metal exposed portion 5 in which the center of the tip surface of the tip portion of the metal pin 1 is opened, the minute amount of the adhesive can be applied more stably and easily at the time of transfer. This makes it possible to automate assembly of higher performance semiconductor devices or high-power semiconductor devices, which can contribute to cost reduction.

  DESCRIPTION OF SYMBOLS 1 metal pin, 2 mounting part (transfer pin side), 3 tip part, 4 fluorine resin coating, 5 metal exposure part, 6 mounting part (apparatus side), 7 supply plate, 8 conductive adhesive, 9 package mounting surface , 10 semiconductor chips, 11 mounting nozzles.

Claims (3)

A transfer pin comprising a metal pin used to apply a conductive adhesive for bonding a semiconductor device to a mounting surface, the transfer pin comprising:
The metal pin has a plurality of protrusions formed at its tip, and a fluorine resin coating adheres to the side surface of the tip,
The tip end face of the protrusion has a metal exposed part for applying a conductive adhesive at the time of transfer, and a part of the side face around the tip face has a predetermined height from which the fluorine-based resin coating is removed. A transfer pin characterized by having a region. A transfer pin comprising a metal pin used to apply a conductive adhesive for bonding a semiconductor device to a mounting surface, the transfer pin comprising:
The metal pin has a fluorine resin coating attached to the side of the tip,
A transfer pin characterized in that a central portion of a tip surface of the tip portion has a metal exposed portion from which a fluorocarbon resin coating is removed for applying a conductive adhesive at the time of transfer. A plurality of protrusions are formed at the tip, a fluorine resin coating is attached to the side surface of the tip, and a metal exposed portion is formed, and a fluorine resin at a predetermined height around a portion of the tip surface of the protrusion A method for adhesive transfer of a semiconductor device, comprising applying a conductive adhesive to a semiconductor device using a metal pin having an area where the coating is removed.
A first step of immersing the tip portion of the metal pin in a conductive adhesive filled tray;
A second step of moving the tip of the metal pin upward;
A third step of pressing the tip end of the metal pin against the adhesive coated surface of the semiconductor device and applying the conductive adhesive;
A fourth step of evacuating the tip of the metal pin from the adhesive coated surface of the semiconductor device;
The adhesive transfer method of the semiconductor device provided with this invention.

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